Water seal for high pressure furnaces



f 28 BaaBz EE Oct. 11, 1955 G. R BARBER 2,720,177

WATER SEAL FOR HIGH PRESSURE FURNACES 1/- FMEA/ACE WALL mwmmm,

WATER INLET INVENTOR. GEOPGE 7E. .BA EBEE BY )FICHE Y, WA T75, EBGEPO/VMNEA/NY A Troie/Veys United States Patent ice WATER SEAL FOR HIGHPRESSURE FURNACES George R. Barber, Drexel Hill, Pa., assignor to TheAllen- Sherman-Holf Company, Wynnewood, Pa., a corporation ofPennsylvania Application August 5, 1954, Serial No. 448,049

6 Claims. (Cl. 11G-165) This invention relates generally to the art ofhandling gases under pressure and is particularly concerned with meansfor preventing the flow of gases through thespace between a powderedfuel burning furnace and its ash hopper.

Fuel burning furnaces have heretofore been provided with seals toprevent the flow of gases through spaces between the ash hopper andtheash discharging part of the furnace. Seals of this type are disclosed inU. S. Patents Nos. 2,275,652 and 2,594,976. The seals of these patentsinclude a trough containing water and a gas impervious curtain dependinginto the water with the trough being connected to the furnace or to thehopper and with the curtain being connected to the other one of thosetwo devices.

While water seals of the types disclosed in the aforesaid patents havebeen found to be satisfactory in extensive commercial use, they possesscertain inherent limitations. Those seals werefrst used on furnaces inwhich the gas pressure was low, amounting to only a few inches A ofwater pressure, and the depth of the water in the seal wascorrespondingly short. As the furnace pressures were increased from timeto time, the depth of the trough in these seals was correspondinglyincreased by increasing the vertical dimensions of the troughs andcurtains. As

the sizes of these parts increased, the seal apparatus became larger andmore cumbersome untilia practical limit to the size of those parts hasbeen reached which, however, will not accommodate the present highpressure or the higher pressures which are in prospect. So far as Iknow, no one has proposed a seal 'which could be used i with the presenthigh pressures or even higher pressures and which would be compact andfree from the objections of excessive size and the other disadvantagesof the seals of the types disclosed in the aforesaid patents.

The present invention aims to provide a new seal for such high pressureand attains that object by a new cornbination of elements which give anew result not attainable by the elements acting separately.

Briefly stated, the present invention provides a plurality of seals eachincluding a liquid-containing trough and a gas impervious curtain andmeans for creating a gas pressure in those seals which balances oroffsets part of the pressure to be sealed.

The present invention will be better understood by those skilled in theart from the following specification taken in connection withtheappended drawings in which:

The figure is a fragmentary, vertical sectional view showing oneembodiment of the present invention applied to a furnace and its hopper.

In the figure, 10 designates a part of the wall dening the ash dischargepassage from a fuel burning furnace. The wall 10 projects downwardlyinto the ash hopper 11 through an opening in its top.

The means for sealing the space between the wall 10 and hopper 11includes the trough member 12, the curtain member 13 and a gas pressureproducer and regulator 14.

y 2,726,177 Patented Oct. 11, 1955 The trough member 12 is positioned inthe ash receiving opening of hopper 11, is connected to the hopper, ex-

tends entirely around the furnace wall and consists of a bottom wall 15and outer, middle and inner vertical walls 16, 17 and 18, respectively,these several walls form- ,.ing outer and inner troughs 19 and 20,respectively, to

may be drawn off from the overflow trough. Water or other liquid may bebrought into the inner trough 20 through pipe 23 which extends from asource of supply through a wall of hopper 11 and through the bottom wall15 of the inner trough. Like liquid may be supplied to the outer trough19 in a similar manner or may be piped into the upper open end of thattrough.

The curtain member 13 of the illustrated seal comprises vertical, outerand inner, gas impervious walls 25 and 26 which are disposed in theouter and inner troughs 19 and ,Zll, respectively, and which areconnected by a horizontal top wall 27. This member 13 is attached to thefurnace wall 10 iniany suitable manner, as, for example, by a gas-tightconnection of wall 28 to member 13 and to the metal shell of furnacewall 10. This wall 28 serves `to position and maintain walls 25 and 26in vertical position between and spaced from the side walls of troughs19 and 20.

Means are provided to create and maintain a gas pressure between wallsor curtains 25 and 26 above liquid `in troughs 19 and 2l). As shown,this means comprises p comprising a vessel 33 and pipe 32 is called abubbler for the sake of brevity.

The above-described apparatus operates substantially as follows: Thetroughs 19 and 20 are filled with water or other liquid and a sufficientamount of the same liquid is placed in vessel 33 to make the distance Dequal to about half the pressure to be sealed, as expressed in inches ofbetween the surfaces of the water in trough 24 on opposite sides ofcurtain 26 is approximately equal to distance D, i. e., about half thepressure within the furnace is offset or balanced by the column of waterin the inner trough 20 above the surface of the water in that trough onthe inner side of the curtain 26. The gas delivered by compressor 30into the curtain member 13 forces liquid down in trough 19 betweencurtain 25 and middle wall 17 and up between curtain 25 and outer wall16, and raises the surface of the liquid in trough 19 outside of curtain25 to a level above the liquid on the other side of curtain 25 to anamount equivalent to about half of the gas pressure within the furnace.The bubbler serves to control the gas pressure delivered into curtainmember 13 for if the gas pressure within the furnace exceeds thepredetermined amount, gas from the compressor will flow through thebubbler, and if the pressure falls below the predetermined amount, gasfrom the compressor will ow into member 13 and will not ow through thebubbler.

In this manner, high gas pressures in the furnace may be sealed bycompact apparatus of short vertical length.

For example, with a two-stage seal, such as is disclosed herein, a gaspressure equivalent to 40 inches of water can be sealed by columns ofwater in troughs 19 and 20 each of which columns. seals against a gaspressure of about 20/ inches of water. In other words, apparatusembodying thisv invention may seal against a gas pressure of 40 inchesand yet be only a little more than 20 inches in overall vertical length.

It will be understood that more than two troughs may be VemployedV in aseal embodying the present invention and that as the number of troughsincreases, the gas pressure which the device can seal may increase orthe vertical height of the apparatus may be decreased.

Having thus described the present invention so that others skilled inthe art may be able to understand and practice the same, I state thatwhat I desire to secure by Letters Patent is defined in what is claimed.

`What is claimed is:

1. Apparatus for sealing a space between the walls of two membersagainst 'ow therethrough of gas under pressure comprising a memberadapted to be attached to one of said walls and deiining a plurality ofvertical, open topped troughs to contain a liquid, a member adapted tobe attached to the other of said walls and including gas imperviouscurtains depending into liquid in each of said troughs, and 'means formaintaining in the space between said curtains and above the liquid insaid troughs gas under pressure equal approximately to the gas pressureto be sealed divided by the' number of open top troughs.

2. Apparatus for sealing a space between the walls of two membersagainst flow therethrough of gas under pressure comprising a memberadaptedv to be attached'to one of said walls and defining a pluralityofvertical, open topped troughs to contain a liquid, a member. adapted tobe attached to the other of said walls and including gas imperviouscurtains depending into liquid in each of said troughs, and means formaintaining in the space between said curtains and above the liquid insaid troughs gas under pressure equal approximately to a predeterminedpart of the pressure of the gas to be sealed, said means including a gascompressor, a bubbler containing a liquid and lines for conducting gasfrom said compressor into the space between said curtains and intoliquid in said bubbler at a predetermined distance below the surface ofthat liquid.

3. Apparatus for sealing a space between the walls of two membersagainst iiow therethrough of gas under pressure comprising a memberadapted to be attached to one of said walls and defining two verticalopen topped troughs to contain water, a member adapted to be attached tothe )ther of said walls and including gas impervious curtains dependinginto water in each of said troughs, and means for maintaining in thespace between said curtains and above the water in said troughs gasunder pressure equal approximately to one half of the pressure of thegas to be sealed. Y

4. Apparatus for sealing a space between the walls of two membersagainst flow therethrough of gas under pressure comprising a memberadapted to be attached to one of said walls and having a bottom wall andvertical, horizontally spaced walls extending upwardly therefrom to formvertical, open topped troughs to contain Water, a member adapted to beattached to the other of said walls and having a horizontal wall andhorizontally spaced, gas impervious walls depending vertically from saidhorizontal wall and into water in each of said troughs, said dependingwalls being spaced horizontally from the walls of said troughs, andmeans for maintaining in the space between said depending walls andabove the water in said troughs gas under pressure equal approximatelyto a predetermined part of the pressure of the gas to be sealed.

5. Apparatus for sealing against escape of gas under pressure from afuel burning furnace comprising an ash hopper having an opening in itsupper portion, a furnace wall extending through said opening anddefining an ash discharge passage, means attached to said hopper,surrounding said furnace wall and having vertical walls defining twolvertical troughs for water, means attached to said furnace wall,surrounding said wall and having two vertical, gas impervious wallsdepending into water in said troughs, and means for maintaining in the4space between said depending walls and above the water in said troughsgas under pressure equal approximately to onehalf ofthe pressure ofthegas to be sealed.

6. Apparatus for sealing against escape of gas under pressure from afuel burning furnace comprising an ash hopper having an opening in itsupper portion, a furnace wall extending through said opening anddefining an ash discharge passage, means attached to said hopper,surrounding 'said furnace wall and having vertical walls deiining twovertical troughs for water, means attached to said furnace wall,surrounding said wall and having two vertical, gas impervious wallsdepending into water in said troughs, and means for maintaining in thespace between said depending walls and above the water in said troughsgas under pressure equal approximately to one-half of the pressure lofthe gas to be sealed, said pressure maintaining means including an aircompressor, a line to conduct air from the compressor into the spacebetween said depending wallsandinto a bubbler, the latter having a depthof water above the outlet of the air thereinto which is approximatelyequivalent to a predetermined part of the gas pressure to be sealed.

vonr Kerpely Nov. 11, 1913 Keith et al Sept. 27, 1938

